1. Field of the Invention
This invention relates to an information filing apparatus.
2. Related Background Art
Recently, office automation has rapidly progressed. Thus there is an increasing tendency that computers are incorporated into office devices which are in turn are interconnected via telecommunication circuits. In order to cope with such computerization and interconnection, it is desirable to use information, to be handled, as electrical signals as much as possible. What satisfies this demand is an electronic filing system which uses an electronic file (a photo disc, a photomagnetic disc, etc.) which converts image information to a digital signal and records it thereon.
The electronic filing system has the big feature that it can record a great amount of image information with high density in the form of an electrical signal to thereby realize reduction of a space for information storage, and high speed search. However, the electronic filing system has the drawback that as the accumulation of information increases, the speed of its search decreases.
In order to solve this problem, applicant has filed Japanese Patent Application No.57899/1985 (Unexamined Published Patent Application No.216022/1986) in which image information read as by a reader is all stored in an erasable photomagnetic disc and image information not so often used is transferred to and stored in an additionally writable non-erasable photo disc. This causes image information used very often to be left in the photomagnetic disc to prevent a decrease in the search efficiency. However, the images which are used very often are stored only in the photomagnetic disc, consequently the important images are in danger of being erased erroneously.